Anyone looking for some reasonable parking and worried about the Stanmore, Canon's Park station car parks being full, you can book a space at Sainsbury's at Kenton (HA3 0JA) via the JustPark site/app. Couple of mins from Kenton tube - 3 stops to Wembley Central, which is on 'our' side of the stadium, I think. All day for just over a fiver. I've booked at other Sainsbury's car parks before and all worked fine.